Hetrick is facing the biggest challenge of his career: finding a connection between decades-old missing person's cases and a slew of unidentified victims. If successful, he could stop a serial killer in his tracks.

A woman is murdered while working the late shift at a motel. Signs point to a crime of passion, but Hetrick knows it isn't so simple. Still, no one imagines it will take 12 years to catch a killer.

The premiere of the true-crime series details the case of a young mother who was beaten and shot to death. While investigators aren't lacking for suspects, the coroner sees signs that it was a crime of passion.

When a young, married couple is discovered in the aftermath of a house fire, firefighters fear they arrived too late. Hetrick suspects that this fire is no accident—and while he may find the truth, will justice be served?

When a woman is killed in her backyard, investigators focus on her family. But Graham believes this is a special kind of assassin who kills for the thrill of it. The clock is ticking; will the murderer be caught before he strikes again?

When the smoke clears from a mysterious car fire, a charred body is discovered in the backseat. Hetrick identifies the victim and in piecing together the secrets of this man's life and death, reveals atrocities no one ever imagined.

In 2009, Hetrick is called to one of the strangest crime scenes of his career: a man has been stabbed to death, his body wrapped in garbage bags. But what is unearthed during the autopsy and murder investigation leads to an even more appalling conclusion.

A woman suffers a seemingly accidental fall down flight of stairs, and dies from a traumatic brain injury. But after the autopsy, Hetrick suspects there is more than meets the eye. Ten years and two more mysterious deaths later, the truth is finally revealed.